This is a prospective study of maternal characteristics which affect infant feeding behavior in the first year of life. Factors associated with choice and duration of breast feeding are being investigated. The specific objectives of the study are as follows: (1) to provide detailed information on the change in the infant feeding pattern over time; (2) to investigate the underlying of the milk insufficiency syndrome; (3) to investigate the relation between maternal employment and choice and duration of breast feeding; (4) to determine the sociocultural differences in infant feeding between two ethnic groups.